Jerem Paul, Herborn Katherine, McCafferty Dominic, McKeegan Dorothy, Nager Ruedi
Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow.
Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow;
J Vis Exp. 2015 Nov 6(105):e53184. doi: 10.3791/53184.
Stress, a central concept in biology, describes a suite of emergency responses to challenges. Among other responses, stress leads to a change in blood flow that results in a net influx of blood to key organs and an increase in core temperature. This stress-induced hyperthermia is used to assess stress. However, measuring core temperature is invasive. As blood flow is redirected to the core, the periphery of the body can cool. This paper describes a protocol where peripheral body temperature is measured non-invasively in wild blue tits (Cyanistes caeruleus) using infrared thermography. In the field we created a set-up bringing the birds to an ideal position in front of the camera by using a baited box. The camera takes a short thermal video recording of the undisturbed bird before applying a mild stressor (closing the box and therefore capturing the bird), and the bird's response to being trapped is recorded. The bare skin of the eye-region is the warmest area in the image. This allows an automated extraction of the maximum eye-region temperature from each image frame, followed by further steps of manual data filtering removing the most common sources of errors (motion blur, blinking). This protocol provides a time series of eye-region temperature with a fine temporal resolution that allows us to study the dynamics of the stress response non-invasively. Further work needs to demonstrate the usefulness of the method to assess stress, for instance to investigate whether eye-region temperature response is proportional to the strength of the stressor. If this can be confirmed, it will provide a valuable alternative method of stress assessment in animals and will be useful to a wide range of researchers from ecologists, conservation biologists, physiologists to animal welfare researchers.
应激是生物学中的一个核心概念，描述了对挑战的一系列应急反应。在其他反应中，应激会导致血流变化，从而使血液净流入关键器官，并使核心体温升高。这种应激诱导的体温过高被用于评估应激。然而，测量核心体温具有侵入性。由于血流被重新导向核心部位，身体外周会冷却。本文描述了一种方案，即使用红外热成像技术对野生蓝山雀（Cyanistes caeruleus）的外周体温进行非侵入性测量。在野外，我们设置了一个装置，通过使用一个诱饵箱将鸟类带到相机前的理想位置。相机在施加轻度应激源（关闭箱子从而捕获鸟类）之前，对未受干扰的鸟类进行一段短时间的热视频记录，并记录鸟类对被困的反应。图像中眼部区域的裸露皮肤是最热的区域。这使得能够从每个图像帧中自动提取眼部区域的最高温度，随后通过进一步的手动数据过滤步骤去除最常见的误差来源（运动模糊、眨眼）。该方案提供了具有精细时间分辨率的眼部区域温度时间序列，使我们能够非侵入性地研究应激反应的动态变化。进一步的工作需要证明该方法在评估应激方面的有用性，例如研究眼部区域温度反应是否与应激源的强度成正比。如果这一点能够得到证实，它将为动物应激评估提供一种有价值的替代方法，并且对从生态学家到保护生物学家、生理学家再到动物福利研究人员等广泛的研究人员都将有用。
